Hydraulic brake



Dec. 22, 936. H. w. BALL ET Al.

HYDRAULIC BRAKE Filed Feb. l5, 1955 M ||m| 9 3 8 3 A v 4^ 3 5 1 0n T 1 .n .vw 6 a W N, fn/l n w u m @,5 WU? 9 AA Patented Dec. 22, 1936 y.umn-:D STAT-Es PAJrEN'r ori-ICE HYDRAULIC BRAKE Application February 13, 1935, SeriaLNo.' 6,356

8 Claims.

This invention relates to improvements in hydraulic brakes, and the primary 'purpose of the invention is to combine Vwith such brakes, an

- electrically operated safety means so constructedv that in case of failure of a hydraulic control means for the brakes, the safety mechanism will come into play and apply the brakes.

Another object of the invention is to combine with the brake vshoe operating mechanism, a solenoid so attached that itwill set the brake in case the uid carrying mechanism should fail. This solenoid is preferably energized and normally holds a compression spring in compression, which spring comes into play and applies the brakes when the solenoid is de-energized.

A further object is to provide a safety device for hydraulic foot operated brakes; the brake pedal being employed to set the safety feature in action automatically in case of a failure of the .20 hydraulic means.

In accordance with the invention, anv electrically controlled mechanism is combined with a conventional foot controlled brake, whereby when the brake pedal is depressed beyond a certain extent, it will act to release the current from a solenoid and allow a spring to set the brake.

WithA the foregoing objects outlined and with other objects in view which will appear as Athe description proceeds, the invention consists in the novel features hereinafter described in detail, illustrated in the accompanying drawing, and more particularly pointed out in the appended claims.

The invention will now be described in detail.

in connection with the accompanying drawing' in which,

Fig. 1 is a side elevation, partly in vertical seetion, of one embodiment of the improved mechamsm.

Fig. 2' is an end view of the same.

Referring to the drawing, 3 designates any suitable elementsuch asa shaft to be controlled by a brake .4 `which cooperates with an upper shoe 5 onn'ected at 'I to an arcshaped lev .pivotally mounted at one end onan Y ij supported by a stationary post I0 that oJ cts upwardly from a stationary base II f1 The lower shoe is pivotally connected to a similar lever I3 that has o n' pivotally mounted at I4 on said,4

An eye-bolt I5 is pivotally the opposite end of thelve through an eye I1 in the" rounding this bolt and functioning to normally maintain the shoes out of contact with the brake drum.

'I'he brake shoes are moved toward the drum by means of a bell-crank lever I9 pivotally 5 mounted on the lever 8`"at the point 20, and havin'g an element 2l engageable with the bolt I5.

One arm of the lever is pivotally connected at 22 to linkage 23 that is operatively associated with a piston, not shown, arranged in a hydraulic 10 bellows type cylinder 24. The hydraulic uid acting on this piston functions to set or apply the brakes, and this fluid is normally controlled by a foot operated valve 25 which controls the flow of4 the fluid through a pipe 26 into the cylin- 15 der. The valve has a foot pedal 21, and when that pedal is depressed to a normal degree, the uid will enter the cylinder 24 and apply the brakes. As thehydraulic mechanism-sometimes falls to function through leakage or the like, we have provided safety mechanism to take care of this disadvantage. In accordance with our invention, a lever 28 has its lower end pivotally connected at 29 to the post I0, and this lever carries 25 a solenoid 30 and a strong compression spring 3|. Normally, the solenoid is held by magnetic attraction in contact with a stationary pole 32 xed tothe post Il), so that the spring is held under compression. l 3 A rod 33 has, one of its ends connected at 34 to the upper end of the lever 28, and its opposite end slidably engages a bearing abutment 35,

pivotally connected at 36 to the upper arm of the bell-crank lever I9. 35

Adjusting nuts 31 and 38 engage threadson the rod 33. By releasing the nut 33, the nut 31 can be turned until the magnet 30 is drawn tight against the pole 32, and at such time, if the current is on, the lever 28 .will be held in 40 engagement with said pole and the spring 3I will be held under compression. lNow, the nut 31 can be backed off a sufficient distance to allow-the bell-crank lever I9 to occupy a position where the brake shoes Will give suihcient .clear- 45 ance for the bake wheel to rotate without friction when the brake mechanism -is released. From this time forward, the mechanism will operate in the usual way, but it will be noted hat the solenoid or electrical magnet 30 is in an 50 triccircuit having a battery 40 and a switch fthe latter being controlled by the'pedal 2'I. lllfh'en the pedal is depressed beyond its usual ange,4 through failure of the hydraulic mechanism, thesiitch will be opened, and the electric 55 energy will be released from the solenoid 30. Consequently', the lever 28 will be released from the pole 32, and the spring 3I will move that lever in a counter-clock-Wise direction, with the 'result that the rod 33 will swing the bell-crank lever I9 in a counter-clock-wise direction about the pivot 20, and thus set the brake.

For balancing up the brake shoes, the ,brake is set in released, position, that is, the magnet 30 is against the pole 32, and the plunger in the brake cylinder 24 is in its lowest position. Then the adjusting nut 5I) arranged between the lever I3 and the base II, is adjusted so that the shoe -6 has about one-thirty second of an inch clearance between it and the brake drum, and the shoe 5 is adusted for clearance by adjusting nuts 5I `and 52 arranged on the eye-bolt I5. 'I'his completes 'the adjustment of the brake. As shown in Fig. l, the lever I3 may be lowered to the dotted line position when the nut 50 is loosened.

If the magnet is released, the brake is applied, or if the foot pedal 21 is pressed down, the hydraulic pressure cylinder shoves up the substantially horizontal arm of the bell-crank lever I9 and applies the brake.

From the foregoing it will be understood that vthe spring 3| is used for applying the brake in case of hydraulic failure, and that the magnet is used to hold the brake in released' position as long as the control switch is in or closed. Of course, the failure of the hydraulic medium, which would allow the foot lever Vto over-travel and open the switch, would de-energize the magnet and allow the compression spring to set the brake.

One embodiment of the invention is described above and illustrated in the accompanying drawing, but it will be apparent to those skilled in the art that changes maybe made in the details disclosed, without departing from the spirit of the invention, as expressed in the claims.

What is claimed and desired to be secured by Letters Patent is:

means cooperating with said second element for holding the member in engagement with said pole, and spring means for moving the member away from the pole when the electro-magnetic means 's de-energized due to abnormal movement l, i said second element, whereby saidrst element is caused to applyv the shoe to the drum in case of iailure of the power means.

2. In braking mechanism, a brake drum, a

brake shoe cooperating therewith, an element for applying said shoe to the drum, power means forv controlling the operation of said element, a second element adapted to be actuated by the operator for 'controlling vthe operation of said power means, a stationary pole, a member movable relatively to said pole and operatively connected to said rst element, electro-magnetic means .operating with said second element for holdingI the member in engagement withsaid pole', and' sprin'g means for moving the membersaway frenir the pole when-the electro-magnetic is deenergized due to abnormal movement of said second element, whereby said rst element is moving the members toward the drum, power l means for actuating said bell-crank lever, a second element adapted to be actuated by the operator for controlling the operation of said power means, a stationary pole, a lever member cooperating with-said pole and operatively connected with said bell-crank lever, electro-magnetic means cooperating with said second element for normally holding the lever member in engagement with said pole, and spring means for moving the lever member away from the pole when the electro-magnetic means vis de-energized due to abnormal movement of said second element,

wherebyk said bell-crank lever cooperates with' said rst element to apply the shoes to the drum.

4. In braking mechanism, a brake drum, a support arranged adjacent tosaid drum, pivoted levers connected to said support, brake shoes carried by said levers and, cooperating with said drum, an eye-bolt connecting said'levers, a spring surrounding said bolt and normally holding the levers in such positions as to maintain the shoes out of contact with the drum, a bell-crank lever pivotally mounted on one of the rst mentioned levers and having rst and second arms, means operatively connecting the second one of said arms to said bolt, power means connected to said second arm for controlling the operation of said shoes,an element adapted to be actuated by the operator for controlling the operation of said power means, a stationary pole, a lever operatively connected to the second arm of the vbell crank lever for actuating the latter in case of a failure -of said power means, electro-magnetic means cooperating with said element for normally holding the last mentioned lever in engagement with said pole, and spring meais for moving the last mentioned lever away from the pole when thev electro-magnetic means is de-energized due to abnormal movement of said element.

5. In braking mechanism, a brake drum, a support arranged adjacent to said drum, pivoted levers connected to said support, brake shoes carried by said levers and cooperating with said drum, an eye-bolt connecting said levers, a spring surrounding said bolt and normally holding the levers in such positions as to maintain the shoes' out of contact with the drum, a bell-crank lever pivotally mounted on one of the ilrst mentioned levers and having iirst and second arms, means operatively connecting the second onev of said arms to said bolt, power means, connected to said second arm for controllingsthegopeation of said lshoes, an element adaptedvtozbe/ctuated bythe operator dfr controlling tlfiegsperation of 'said power means, a stationary jpole, aleverfoperatively connected to the second arm of the bell-'- crank lever for actuating/ the latter in case of la failure of said power means,A electro-magnetic means' cooperating with said element for nor- `mallyholding the'last mentioned lever in engagemritwitlrsaidr pole, and spring means for moving the last. mentioned lever away from the pole v.-,vvhen the electro-magnetic means is-de-energized,

said electro-magnetic means being controlled by said element. I f

6.--Braking mechanism comprising a drum, brake shoes cooperating therewith, means for contrlling the operation of said shoes and including a foot pedal, a stationary pole, a member movable toward and away from said pole and operatively connected to the last mentioned means, electro-magnetic means cooperating with said first mentioned means for holding said member in engagement with said pole, means'for controlling the electro-magnetic means by said pedal, and means for moving said member away from -said pole when the electro-magnetic means is deenergized:

7. In braking mechanism, a brake drum, a brake shoe cooperating therewith, an element for applying said shoe to the drum, hydraulic means for controlling the operation of said lelement and provided with a control valve, a second element adapted to be actuated by the operator for controlling said valve, spring means operatively connected with the first element forapplying said shoe to the drum, electrically operated means for controlling said spring means, and a switch for controlling said electrical means, said switch being arranged for operation by said second element when said second element is moved to4 an abnormal degree, whereby said rst element is caused to apply the shoe to the drum in case of failure of the hydraulic means.

8. Braking. mechanism comprising a drum, brake shoes cooperating therewith, means for controlling the operation of said shoes'and including an element adapted to be moved by the operator, a stationary pole, a member movable toward and away from said pole and operatively connected to the last-mentioned means, electromagnetic means cooperating with said first-mentioned means for holding said member in en.- gagement with said pole, means for controlling the electro-magnetic means by said element, and means for moving said member away from said pole when the electro-magnetic means is deenergized.

HARVEY W. BALL.

JOHN KLOOS.

OSCAR S. JEFFRIES. 

